Comparison of Zybio Kit and saponin in-house method in rapid identification of bacteria from positive blood cultures by EXS2600 matrix-assisted laser desorption ionization time-of-flight mass spectrometry system.

We evaluated the performance of Zybio EXS2600 matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) (Zybio Inc., Chongqing, China) for the identification of bacteria from positive blood culture (BC) bottles using Blood Culture Positive Sample Pretreatment Kit (Zybio Inc., Chongqing, China) in comparison to an in-house saponin method. Following a positive signal by the BACTEC™ FX system, confirmation of identification was achieved using subcultured growing biomass used for MALDI-TOF MS analysis. A total of 94 positive BC bottles with 97 bacterial isolates were analyzed. The overall identification rates at the genus and species levels for the saponin method were 89.7% (87/97) and 74.2% (72/97), respectively. With the Zybio Kit, 88.7% (86/97) and 80.4% (78/97) of microorganisms were correctly identified to the genus and species levels, respectively. The saponin method identified 65.3% (32/49) of Gram-positive bacteria at the species level, whereas the Zybio Kit achieved a higher species-level identification rate of 79.6% (39/49) (p = 0.1153). The saponin method with additional on-plate formic acid extraction showed a significantly higher overall identification rate in comparison to the saponin method without that step for both genus (87.6% [85/97] vs. 70.1% [68/97], p = 0.0029) and species level (70.1% [68/97] vs. 46.4% [45/97], p = 0.0008). Identification rates of Gram-negative bacteria showed a higher identification rate, however, not statistically significant with additional Zybio Kit protocol step on both genus (85.4% [41/48] vs. 81.3% [39/48], p = 0.5858) and species level (77.1% [37/48] vs. 75% [36/48], p = 0.8120). Zybio Kit could offer an advantage in species-level identification, particularly for Gram-positive bacteria. The inclusion of on-plate formic acid extraction in the saponin method notably enhanced identification at both genus and species levels for Gram-positive bacteria. The extended protocol provided by the Zybio Kit could potentially offer an advantage in the identification of Gram-negative bacteria at both genus and species levels. Enhancements to the Zybio EXS2600 MALDI-TOF instrument software database are necessary.

Validation of short culture method for rapid bacterial identification of blood cultures via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

BACKGROUND: Development of rapid bacterial identification from blood cultures has been an area of intense study in diagnostic microbiology. Shortened turnaround time coupled with antimicrobial stewardship interventions have been shown to improve patient outcomes and decrease healthcare-associated costs. OBJECTIVES: We report the validation of a short incubation method for Gram-positive and Gram-negative bacterial identification utilizing MALDI-TOF MS without additional instrumentation, processing or cost compared with current practice. METHODS: Prospective, observational, single-centre study in a quaternary care academic hospital encompassing 376 blood cultures subjected to bacterial identification after short incubation periods of 3-4 and 6-8 h. RESULTS: There was 97.5% species-level identification agreement with tests undertaken after 3-4 h incubation with 83.6% isolates identified, and 99.7% species-level identification agreement after 6-8 h incubation with 96.7% isolates identified. CONCLUSIONS: The short incubation method provides a rapid MALDI-TOF MS bacterial identification method, reducing turnaround time by 10-18 h compared with standard practice without additional cost, processing or instrumentation.

Augmented pathogen detection in brain abscess using metagenomic next-generation sequencing: a retrospective cohort study.

Brain abscess is a severe infection characterized by the accumulation of pus within the brain parenchyma. Accurate identification of the causative pathogens is crucial for effective treatment and improved patient outcomes. This 10-year retrospective, single-center study aimed to compare the detection performance of conventional culture methods and metagenomic next-generation sequencing (mNGS) in brain abscess. We reviewed 612 patients diagnosed with brain abscess and identified 174 cases with confirmed etiology. The median age was 52 years, with 69.5% males. Culture tests predominately identified gram-positive bacteria, particularly Streptococcus spp. Gram-negative bacteria, including Klebsiella spp., were also detected. However, mNGS revealed a more diverse pathogen spectrum, focusing on anaerobes (e.g., Fusobacterium spp., Parvimonas spp., Porphyromonas spp., Prevotella spp., and Tannerella spp.). mNGS exhibited significantly higher overall pathogen-positive rates in pus samples (85.0% vs 50.0%, P = 0.0181) and CSF samples (84.2% vs 7.9%, P < 0.0001) compared to culture. Furthermore, the detection rates for anaerobes displayed a notable disparity, with mNGS yielding significantly higher positive detections in both pus samples (50.0% vs 10%, P = 0.0058) and CSF samples (18.4% vs 0%, P = 0.0115) when compared to culture methods. The assistance of mNGS in pathogen detection, particularly anaerobes in brain abscess, was evident in our findings. mNGS demonstrated the ability to identify rare and fastidious pathogens, even in culture-negative cases. These results emphasize the clinical value of mNGS as a supplement for brain abscess, enabling more comprehensive and accurate pathogen identification.IMPORTANCEThe accurate identification of pathogens causing brain abscess is crucial for effective treatment and improved patient outcomes. In this 10-year retrospective study, the detection performance of conventional culture methods and metagenomic next-generation sequencing (mNGS) was compared. The study analyzed 612 patients with brain abscess and confirmed etiology in 174 cases. The results showed that culture tests predominantly identified gram-positive bacteria, while mNGS unveiled a broader diverse pathogen spectrum, particularly anaerobes. The mNGS method exhibited significantly higher overall rates of pathogen positivity both in pus and cerebrospinal fluid (CSF) samples, surpassing the culture methods. Notably, mNGS detected a significantly higher number of anaerobes in both pus and CSF samples compared to culture methods. These findings underscore the clinical value of mNGS as a supplement for brain abscess diagnosis, enabling more comprehensive and accurate pathogen identification, particularly for rare and fastidious pathogens that evade detection by conventional culture methods.

A comparative study of a rapid phenotypic antimicrobial susceptibility testing system directly from positive blood cultures to the disk diffusion and VITEK 2 methods.

BACKGROUND: Sepsis is a life-threatening condition that impacts 49 million people annually and causes 11 million deaths worldwide. Surviving bloodstream infections (BSIs) depends on the rapid administration of effective antimicrobial treatment, underscoring a need for rapid antimicrobial susceptibility testing (AST). AIM: To evaluate the performance of Quantamatrix's dRAST v2.5 system (Seoul, South Korea) for AST directly from positive blood cultures as compared to the Disk-Diffusion (DD) and VITEK 2 methods. METHODS: The study included 191 positive blood cultures from clinical samples and spiked blood culture bottles. Following Gram staining and species-level identification, AST was performed by VITEK 2 and standard DD methods using CLSI (2021) interpretation. RESULTS: dRAST demonstrated very good AST performance for a Gram-negative isolate, and good performance for Gram-positive isolates, meeting CLSI criteria for the acceptance of a new method. Antimicrobials that were not considered verified compared to VITEK 2 and DD were cefazolin, ceftazidime, meropenem, and trimethoprim/sulfamethoxazole for Gram-negatives and clindamycin, erythromycin, penicillin, and oxacillin for Gram-positives. dRAST ESBL detection results were strongly correlated with the ESBL phenotypes obtained with other methods. Additional resistance mechanisms were in concordance with traditional tests. CONCLUSIONS: dRAST demonstrated good AST performance, meeting CLSI criteria for most relevant antibiotics. dRAST was associated with a significant reduction in time-to-results, labor, and the subjectivity of result analyses, making it a valuable addition to efforts supporting the treatment of patients with bacteremia. AST (antimicrobial susceptibility test), blood culture, dRAST, rapid methods, sepsis, turnaround time (TAT).

Prevalence and antimicrobial resistance of bacterial meningitis in China from 2017 to 2021: a multicenter retrospective study.

INTRODUCTION: This study aims to investigate the changing epidemiology and antimicrobial susceptibility of bacteria isolated from cerebrospinal fluid (CSF) in the Shandong region. METHODOLOGY: We conducted a retrospective analysis of bacterial distribution and resistance patterns in CSF samples, utilizing data from the SPARSS network and analyzed with WHONET 5.6 software. RESULTS: A total of 3968 pathogenic bacterial strains were isolated, consisting of 70.6% Gram-positive bacteria, 27.2% Gram-negative bacteria, and 0.2% fungi. The six most commonly detected bacteria were coagulase-negative staphylococcus, Acinetobacter baumannii, Klebsiella pneumoniae, Streptococcus pneumoniae, Escherichia coli, and staphylococcus aureus. Analysis revealed gender and seasonal variations in the distribution of CSF pathogens, with a higher incidence observed in males and during autumn compared to other seasons. The susceptibility profiles of these bacterial species varied significantly, with many exhibiting multidrug resistances. A. baumannii showed a high resistance rate to cephalosporins and carbapenems but was sensitive to tigecycline and polymyxins. For treating multidrug-resistant A. baumannii infections, polymyxin-based combinations with tigecycline or sulbactam are recommended for adults, while tigecycline combined with meropenem is suggested for children. Enterobacteriaceae species were generally sensitive to carbapenems, such as meropenem and other carbapenems that can penetrate the blood-brain barrier can be recommended. Linezolid and vancomycin are the first choice for treating common gram-positive bacterial infections. CONCLUSIONS: The high resistance rates observed among common CSF isolates and their varied distributions across different demographics highlight the necessity for customized treatment strategies.

Effective RNA isolation method for gram-positive and acid-fast bacteria: metamorphosed from conventional RNA isolation techniques.

The RNA-based study provides an excellent indication of an organism's gene expression profile. Obtaining high-yield and high-purity RNA from Gram-positive and acid-fast bacteria is difficult without high-end kits and facilities. We optimised effective and simple protocol for RNA isolation that is a combination of enzymatic, physical and chemical treatment to disrupt cells. We successfully isolated high quality intact total RNA with yields ranging from 23.13 ± 0.40 to 61.51 ± 0.27 µg and the 260/280 purity ratio of 1.95 ± 0.01 to 2.05 ± 0.01 from Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, and Mycobacterium smegmatis. These results represents a significantly enhanced yield and purity compared to other combination of techniques which we performed. Compared to previous studies the yield obtained by this method is high for the studied organisms. Furthermore the yielded RNA was successfully used for downstream applications such as quantitative real time PCR. The described method can be easily optimised and used for various bacteria.

Array-based specific classification of bacterial species via ligands with dimethylamino/amino groups.

The early detection of bacterial species plays a crucial role in patient prognosis and the development of effective therapeutic regimens. This study introduces an accessible and promising colorimetric sensor array designed to classify gram-positive (G+) and gram-negative (G-) bacterial species. The classification relies on 6 chemical ligands with dimethylamino/amino groups as sensing elements and silver nanotriangles as colorimetric probes. Using these specific sensor arrays, we successfully differentiated G- and G+ bacterial species and discriminated individual bacterial strains, and the sensors exhibited remarkable reproducibility and high sensitivity. Moreover, the sensor array can identify bacterial mixtures and bacteria at varying concentrations, underscoring its versatility. In summary, this sensor array offers an effective tool for bacterial analysis with promising applications in the field of biomedical diagnostics.

Nasopharyngeal carriage, antimicrobial susceptibility patterns, and associated factors of Gram-positive bacteria among children attending the outpatient department at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia.

BACKGROUND: Gram-positive bacteria residing in the nasopharynx can lead to severe illnesses in children, such as otitis media, pneumonia, and meningitis. Despite the potential threat, there is a lack of comprehensive data regarding the carriage rates of these bacteria among children in outpatient departments in the study area. OBJECTIVE: This study aimed to assess the nasopharyngeal carriage, antimicrobial resistance patterns, and associated factors of Gram-positive bacteria among children attending the outpatient department at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia. METHODS: A hospital-based cross-sectional study was conducted from May 1, 2023, to August 30, 2023. A total of 424 nasopharyngeal swab samples were collected using sterile nasopharyngeal swabs, inoculated on Blood Agar and Mannitol Salt Agar plates, and identified through colony morphology, Gram stain, and biochemical tests. Antimicrobial susceptibility of the identified bacterial isolates was determined employing both the Kirby-Bauer and modified Kirby-Bauer methods. D-tests were conducted using clindamycin and erythromycin discs to detect inducible clindamycin resistance, while cefoxitin disc tests were utilized to ascertain methicillin resistance. Data entry was executed using Epi-Data version 4.6, and subsequent analysis was performed utilizing SPSS version 25. Bivariable and multivariable logistic regression analyses were employed to identify associated factors. An adjusted odds ratio at a 95% confidence interval with a P-value of < 0.05 was considered statistically significant. RESULTS: The overall nasopharyngeal carriage rate of Gram-positive bacteria was 296/424 (69.8%, 95% CI: 65.3-74.0). Staphylococcus aureus was the most prevalent 122/424 (28.8%), followed by Streptococcus pneumoniae 92/424 (21.7%). Methicillin resistance was observed in 19/122 (15.6%) of S. aureus and 3/60 (5%) of coagulase-negative staphylococcus (CoNS) species. Inducible clindamycin resistance was 10/122 (8.2%) in S. aureus and 4/53 (7.5%) in coagulase-negative staphylococcus species. Multidrug resistance was found in 146/296 (49.3%, 95% CI: 43.6-55.0) of the isolates. Associated factors with a bacterial carriage were large family size (AOR = 3.061, 95% CI: 1.595-5.874, P = 0.001), having siblings under five years old (AOR = 1.991, 95% CI: 1.196-3.313, P = 0.008), indoor cooking (AOR = 2.195, 95% CI: 1.275-3.778, P = 0.005), an illiterate mother (AOR = 3.639, 95% CI: 1.691-7.829, P = 0.001), and hospital visits (AOR = 2.690, 95% CI: 1.405-5.151, P = 0.003). CONCLUSION: The study found a high nasopharyngeal carriage of Gram-positive bacteria in outpatient children, including notable levels of methicillin-resistant S. aureus and multi-drug-resistant isolates. Clindamycin, rifampin, and erythromycin were the most effective antimicrobials for the tested isolates. Factors contributing to bacterial carriage include visits to healthcare facilities, larger family sizes, having younger siblings, maternal illiteracy, and indoor cooking. This emphasizes the need for methicillin-resistant S. aureus surveillance in pediatric outpatient settings and community health education, especially for children's guardians. Additionally, improving household ventilation by separating kitchens from sleeping areas and regular screening of younger siblings in healthcare environments were recommended to reduce bacterial transmission within family members. The study also called for studies with advanced procedures like minimum inhibitory concentration testing and molecular characterization to better comprehend the resistance patterns and genes in circulating bacteria.

Microbiological characterization of neuropathic diabetic foot infection: a retrospective study at a Portuguese tertiary hospital.

Diabetic foot infection imposes a significant burden and is the major cause of nontraumatic limb amputation. Adequate patient management with effective antibiotic therapy is crucial.This retrospective cohort study aimed to characterize the microbiology and resistance patterns of moderate to severe neuropathic diabetic foot infection in patients hospitalized at a tertiary referral hospital between January 2020 and June 2023. Deep tissue specimens from ulcers were collected for culture.Sixty inpatients were included (62% male, mean age 59.1 ± 11.5 years). Osteomyelitis was present in 90% of the patients. Among 102 microorganisms (average of 1.91 ± 1.25 pathogens per patient), 60.8% were gram-positive bacteria, 31.4% were gram-negative, 3.92% were anaerobic bacteria, and 3.92% were fungi. Staphylococcus aureus (19%) and Enterococcus faecium (17%) were the most common. Pseudomonas aeruginosa (8%) and bacteria of the Enterobacterales family (24%) accounted for all the isolated gram-negative bacteria. Sixteen percent of Staphylococcus aureus and 67% of coagulase-negative Staphylococci were resistant to methicillin. Resistance to ampicillin was found in 11% of Enterococci. All Pseudomonas aeruginosa isolates were sensitive to piperacillin-tazobactam, ceftazidime, or cefepime. Among the Enterobacterales, resistance rates were 35% for piperacillin-tazobactam, 38% for ceftazidime, 21% for cefepime, and 13% for carbapenems.Although the prevalence of methicillin-resistant staphylococci was lower than that in other studies, carbapenem resistance among gram-negative bacteria warrants attention. This study highlights the importance of understanding local epidemiology for effective diabetic foot infection management and resistance mitigation.

Isolation and genomic analysis of "Metallumcola ferriviriculae" MK1, a Gram-positive, Fe(III)-reducing bacterium from the Soudan Underground Mine, an iron-rich Martian analog site.

The Soudan Underground Mine State Park, found in the Vermilion Iron Range in northern Minnesota, provides access to a ~ 2.7 billion-year-old banded iron formation. Exploratory boreholes drilled between 1958 and 1962 on the 27th level (713 m underground) of the mine intersect calcium and iron-rich brines that have recently been subject to metagenomic analysis and microbial enrichments. Using concentrated brine samples pumped from a borehole depth of up to 55 m, a novel Gram-positive bacterium was enriched under anaerobic, acetate-oxidizing, and Fe(III) citrate-reducing conditions. The isolated bacterium, designated strain MK1, is non-motile, rod-shaped, spore-forming, anaerobic, and mesophilic, with a growth range between 24°C and 30°C. The complete circular MK1 genome was found to be 3,720,236 bp and encodes 25 putative multiheme cytochromes, including homologs to inner membrane cytochromes in the Gram-negative bacterium Geobacter sulfurreducens and cytoplasmic membrane and periplasmic cytochromes in the Gram-positive bacterium Thermincola potens. However, MK1 does not encode homologs of the peptidoglycan (CwcA) and cell surface-associated (OcwA) multiheme cytochromes proposed to be required by T. potens to perform extracellular electron transfer. The 16S rRNA gene sequence of MK1 indicates that its closest related isolate is Desulfitibacter alkalitolerans strain sk.kt5 (91% sequence identity), which places MK1 in a novel genus within the Desulfitibacteraceae family and Moorellales order. Within the Moorellales order, only Calderihabitans maritimus strain KKC1 has been reported to reduce Fe(III), and only D. alkalitolerans can also grow in temperatures below 40°C. Thus, MK1 represents a novel species within a novel genus, for which we propose the name "Metallumcola ferriviriculae" strain MK1, and provides a unique opportunity to study a cytochrome-rich, mesophilic, Gram-positive, spore-forming Fe(III)-reducing bacterium.IMPORTANCEThe Soudan Underground Mine State Park gives access to understudied regions of the deep terrestrial subsurface that potentially predate the Great Oxidation Event. Studying organisms that have been relatively unperturbed by surface conditions for as long as 2.7 billion years may give us a window into ancient life before oxygen dominated the planet. Additionally, studying microbes from anoxic and iron-rich environments can help us better understand the requirements of life in analogous environments, such as on Mars. The isolation and characterization of "Metallumcola ferriviriculae" strain MK1 give us insights into a novel genus and species that is distinct both from its closest related isolates and from iron reducers characterized to date. "M. ferriviriculae" strain MK1 may also act as a model organism to study how the processes of sporulation and germination are affected by insoluble extracellular acceptors, as well as the impact of spores in the deep terrestrial biosphere.

Evaluation of Quantamatrix dRASTTM system for rapid antimicrobial susceptibility testing of bacterial isolates from positive blood cultures, in comparison with commercial Micronaut broth microdilution system.

Antimicrobial susceptibility testing (AST) from blood culture (BC) may take several days, limiting the eventual impact on antimicrobial stewardship. Hence, rapid AST systems represent a valuable support in shorting the time-to-response. In this work, the Quantamatrix dRASTTM system (dRAST) was evaluated for rapid AST on 100 monomicrobial BCs (50 Gram-negatives and 50 Gram-positives), including several isolates with clinically relevant resistance mechanisms. AST results were provided in 6-hours, on average. Compared to Micronaut (Merlin) system based on broth microdilution, dRAST exhibited an overall categorical agreement of 92.5 %, essential agreement of 89.0 %, and mean bias of 15.9 %. Category overestimation (potentially leading to unnecessary high-dosage treatment or to exclude active agents) and category underestimation (potentially leading to underdosing or using ineffective agents) were observed in 4.3 % and 3.1 % of cases, respectively. Even though several issues were reported, results confirmed the potential contribution of dRAST to shorten the BCs clinical microbiology workflow and management.

Etiological structure and antibiotic resistance pattern of burn wound infections in hospitalized patients - a one-center study in Varna, Bulgaria.

In the present retrospective study, we have evaluated bacterial pathogens isolated from patients admitted to the Burn Care Unit at the Military Medical Academy, Varna, Bulgaria over a three-year period (January 2019 - December 2021). We also tried to summarize the corresponding antibiotic resistance pattern of the isolated infectious agents. A total of 1030 isolates were obtained from 1912 burn wound samples investigated. There were 553 Gram-positive (53.7%) and 477 Gram-negative (46.3%) isolates. The most common isolates for the study period were coagulase-negative staphylococci (CoNS) (25%), Pseudomonas aeruginosa (17.7%), Staphylococcus aureus (16.6%), Acinetobacter baumannii (7.7%), Enterobacter spp. (7.1%), Escherichia coli (4.4%), Proteus spp. (3.4%), and Klebsiella spp. (2.9%). Glycopeptide antibiotics and linezolid were the most effective drugs against gram-positive isolates, followed by amikacin (for synergistic combinations), whereas colistin, imipenem, meropenem, cefoperazon/sulbactam, and piperacillin/tazobactam were the most active drugs against Gram-negative isolates, and colistin, ampicillin/sulbactam - against A. baumannii.

Capabilities of GPT-4o and Gemini 1.5 Pro in Gram stain and bacterial shape identification.

Aim: Assessing the visual accuracy of two large language models (LLMs) in microbial classification.Materials & methods: GPT-4o and Gemini 1.5 Pro were evaluated in distinguishing Gram-positive from Gram-negative bacteria and classifying them as cocci or bacilli using 80 Gram stain images from a labeled database.Results: GPT-4o achieved 100% accuracy in identifying simultaneously Gram stain and shape for Clostridium perfringens, Pseudomonas aeruginosa and Staphylococcus aureus. Gemini 1.5 Pro showed more variability for similar bacteria (45, 100 and 95%, respectively). Both LLMs failed to identify both Gram stain and bacterial shape for Neisseria gonorrhoeae. Cumulative accuracy plots indicated that GPT-4o consistently performed equally or better in every identification, except for Neisseria gonorrhoeae's shape.Conclusion: These results suggest that these LLMs in their unprimed state are not ready to be implemented in clinical practice and highlight the need for more research with larger datasets to improve LLMs' effectiveness in clinical microbiology.

This study looked at how well large language models (LLMs) could identify different types of bacteria using images, without having any specific training in this area beforehand.We tested two LLMs with image analysis capabilities, GPT-4o and Gemini 1.5 Pro. These models were asked to determine whether bacteria were Gram-positive or Gram-negative and whether they were round (cocci) or rod-shaped (bacilli). We used 80 images of four stained bacteria from a labeled database as a reference for this test.GPT-4o was more accurate in identifying both the Gram stain and shape of the bacteria compared with Gemini 1.5 Pro. GPT-4o had excellent accuracy in correctly classifying the Gram stain and bacterial shape of Clostridium perfringens, Pseudomonas aeruginosa and Staphylococcus aureus. Gemini 1.5 Pro had mixed results for these bacteria. However, both models struggled with Neisseria gonorrhoeae, failing to correctly identify its Gram stain and shape.The study shows that while these LLMs have potential, they are not ready to be implemented in clinical practice. More research and larger datasets are needed to improve their accuracy in clinical microbiology.

Impact of diurnal temperature variations on sputum bacterial detection in hospitalized patients with acute COPD exacerbation: a retrospective study from Fuzhou, China.

OBJECTIVE: To investigate the association between meteorological data three days before admission and the status of sputum pathogens culture in hospitalized patients with Acute exacerbation of Chronic obstructive pulmonary disease (AECOPD) and respiratory infections. METHODS: Data from 1,370 AECOPD patients (80.66% males, approximately 80% age > 70) with respiratory infections hospitalized in Fujian Provincial Hospital between December 2013 and December 2019 were collected. This cohort comprised, along with concurrent meteorological data from Fuzhou. Group differences were analyzed to compare the meteorological data three days prior to admission between patients with positive sputum pathogen cultures and those without. Logistic regression models were employed to investigate the association between meteorological parameters and the status of sputum pathogen cultures in patients with AECOPD and respiratory infections. Sensitivity analyses was conducted among the hospitalized patients from 2013 to 2016 and 2017-2019. Stratified analysis was performed to explore the factors affecting the effect of temperature differences and their interactions. RESULTS: 578(42.19%) cases had a positive sputum culture report indicating pathogen growth. 323 cases were found with Gram-negative bacteria, 160 with Gram-positive bacteria, and 114 with fungi. Uni-variate analysis revealed statistical differences in DTD three days prior to admission (DTD-3d) between the positive and negative sputum culture groups (p = 0.019). Multivariate analysis indicated that an increase in the risk of positive sputum pathogen cultures was associated with greater DTD three days before admission (DTD-3d), with OR1.657 (95%CI [ 1.328-1.981]). The risk of positive sputum pathogen cultures was higher in groups with greater DTD-3d. The findings were consistent across different admission periods. Stratified analysis showed that patients without respiratory failure were more affected by DTD-3d, and an interaction effect was observed (p < 0.001). CONCLUSION: In coastal areas, the diurnal temperature difference three days prior to admission affects the sputum pathogen status in AECOPD patients with respiratory infections.

Short-term culture for rapid identification by mass spectrometry and automated antimicrobial susceptibility testing from positive bottles.

BACKGROUND: Early and appropriate antibiotic treatment improves the clinical outcome of patients with sepsis. There is an urgent need for rapid identification (ID) and antimicrobial susceptibility testing (AST) of bacteria that cause bloodstream infection (BSI). Rapid ID and AST can be achieved by short-term incubation on solid medium of positive blood cultures using MALDI-TOF mass spectrometry (MS) and the BD M50 system. The purpose of this study is to evaluate the performance of rapid method compared to traditional method. METHODS: A total of 124 mono-microbial samples were collected. Positive blood culture samples were short-term incubated on blood agar plates and chocolate agar plates for 5 ∼ 7 h, and the rapid ID and AST were achieved through Zybio EXS2000 MS and BD M50 System, respectively. RESULTS: Compared with the traditional 24 h culture for ID, this rapid method can shorten the cultivation time to 5 ∼ 7 h. Accurate organism ID was achieved in 90.6% of Gram-positive bacteria (GP), 98.5% of Gram-negative bacteria (GN), and 100% of fungi. The AST resulted in the 98.5% essential agreement (EA) and 97.1% category agreements (CA) in NMIC-413, 99.4% EA and 98.9% CA in PMIC-92, 100% both EA and CA in SMIC-2. Besides, this method can be used for 67.2% (264/393) of culture bottles during routine work. The mean turn-around time (TAT) for obtaining final results by conventional method is approximately 72.6 ± 10.5 h, which is nearly 24 h longer than the rapid method. CONCLUSIONS: The newly described method is expected to provide faster and reliable ID and AST results, making it an important tool for rapid management of blood cultures (BCs). In addition, this rapid method can be used to process most positive blood cultures, enabling patients to receive rapid and effective treatment.

The MATH test. A three-phase assay?

This study aimed to investigating the possible interference caused by glass test tubes on the quantification of bacterial adhesion to hydrocarbons by the MATH test. The adhesion of four bacteria to hexadecane and to glass test tubes was evaluated employing different suspending polar phases. The role of the ionic strength of the polar phase regarding adhesion to glassware was investigated. Within the conditions studied, Gram-positive bacteria adhered to both the test tube and the hydrocarbon regardless of the polar phase employed; meanwhile, Escherichia coli ATCC 25922 did not attach to either one. The capacity of the studied microorganisms to adhere to glassware was associated with their electron-donor properties. The ionic strength of the suspending media altered the patterns of adhesion to glass in a strain-specific manner by defining the magnitude of electrostatic repulsion observed between bacteria and the glass surface. This research demonstrated that glass test tubes may interact with suspended bacterial cells during the MATH test under specific conditions, which may lead to overestimating the percentage of adhesion to hydrocarbons and, thus, to erroneous values of cell surface hydrophobicity.

Antimicrobial resistance among pregnant women with urinary tract infections is on rise: Findings from meta-analysis of observational studies.

Pregnant women have a higher risk of urinary tract infections (UTIs) compared to non-pregnant women, making antibiotics necessary for treatment. However, prescribing antibiotics without culture and sensitivity tests may contribute to antimicrobial resistance. A meta-analysis using R was conducted to determine the prevalence of antibiotic resistance patterns in UTIs among pregnant women. We identified observational studies published in the last 10 years and used a random effects model to calculate the pooled prevalence. The prevalence of Gram-negative organisms causing UTIs in pregnant women was 67 %, while Gram-positive organisms were 22 %. The burden of Gram-positive organisms exhibiting antimicrobial resistance was very high at 95 %, primarily to ampicillin. The most common Gram-negative organisms exhibiting antimicrobial resistance were E. coli, Klebsiella, and Pseudomonas aeruginosa, while the most common Gram-positive organisms resistant to antibiotics were Staphylococcus aureus and coagulase-negative Staphylococcus. Sensitivity and culture testing are recommended for effective treatment in pregnant women with UTIs.

Prevalence of multi-drug resistant bacteria in intensive care units at Tripoli University Hospital, Tripoli, Libya.

Among hospitalized patients worldwide, infections caused by multidrug-resistant (MDR) bacteria are a major cause of morbidity and mortality. This study aimed to isolate MDR bacteria from five intensive care units (ICUs) at Tripoli University Hospital (TUH). A prospective cross-sectional study was conducted over a seven-month period (September 2022 to March 2023) across five ICUs at TUH. A total of 197 swabs were collected from Patients', healthcare workers' and ICUs equipment. Samples collected from patients were nasal swabs, oral cavity swabs, hand swabs, sputum specimens, skin swabs, umbilical venous catheter swabs, and around cannula. Swabs collected from health care workers were nasal swabs, whereas ICUs equipment's samples were from endotracheal tubes, oxygen masks, and neonatal incubators. Identification and antimicrobial susceptibility test was confirmed by using MicroScan auto SCAN 4 (Beckman Coulter). The most frequent strains were Gram negative bacilli 113 (57.4%) with the predominance of Acinetobacter baumannii 50/113 (44%) followed by Klebsiella pneumoniae 44/113 (40%) and Pseudomonas aeruginosa 6/113 (5.3%). The total Gram positive bacterial strains isolated were 84 (42.6%), coagulase negative Staphylococci 55 (66%) with MDRs (89%) were the most common isolates followed by Staphylococcus aureus 15 (17.8%). Different antibiotics were used against these isolates; Gram- negative isolates showed high resistance rates to ceftazidime, gentamicin, amikacin and ertapenem. A. baumannii were the most frequent MDROs (94%), and the highest resistance rates in Gram-positive strains were observed toward ampicillin, oxacillin, ampicillin/sulbactam and Cefoxitin, representing 90% of total MDR Gram-positive isolates. ESBL and MRS were identified in most of strains. The prevalence of antibiotic resistance was high for both Gram negative and Gram positive isolates. This prevalence requires strict infection prevention and control intervention, continuous monitoring, implementation of effective antibiotic stewardship, immediate, concerted and collaborative action to monitor its prevalence and spread in the hospital.

Monitoring of antimicrobial resistance in respiratory tract pathogens during the COVID-19 pandemic: A retrospective study.

To understand the distribution and antimicrobial resistance (AMR) of pathogens in respiratory samples in Changle District People's Hospital in Fujian Province in recent years, and provide empirical guidance for infection control and clinical treatment in the region. A retrospective analysis was conducted on 5137 isolates of pathogens from respiratory samples collected from 2019 to 2022. The AMR patterns were systematically analyzed. For research purposes, the data was accessed on October 12, 2023. A total of 3517 isolates were included in the study, including 811 (23.06%) gram-positive bacteria and 2706 (76.94%) gram-negative bacteria. The top 3 gram-positive bacteria were Staphylococcus aureus with 455 isolates (12.94%), Streptococcus pneumoniae with 99 isolates (2.81%), and Staphylococcus hemolytic with 99 isolates (2.81%). The top 3 gram-negative bacteria were Klebsiella pneumoniae with 815 isolates (23.17%), Pseudomonas aeruginosa with 589 isolates (16.75%), and Acinetobacter baumannii with 328 isolates (9.33%). The proportion of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and K pneumoniae fluctuated between 41.9% and 70.5%, and 18.6% and 20.9%, respectively. The resistance rates of E coli, K pneumoniae, P aeruginosa, and A baumannii to carbapenems were 2.36%, 8.9%, 18.5%, and 19.6%, respectively. The prevalence of methicillin-resistant S aureus (MRSA) was 48.55%, but it decreased to 38.4% by 2022. The resistance rate of Staphylococcus haemolyticus to methicillin was 100%, and 1 case of vancomycin-resistant strain was detected. K pneumoniae, P aeruginosa, A baumannii, and S aureus are the main pathogens in respiratory samples. Although the resistance rates of some multidrug-resistant strains have decreased, ESBL-producing Enterobacteriaceae, carbapenem-resistant bacteria have still increased. Therefore, it is necessary to strengthen the monitoring of pathogen resistance, promote rational use of antibiotics, and promptly report findings.

A sandwich-structured multifunctional platform based on self-assembled Ti3C2Tx@Au NPs films, antibiotics, and silent region SERS probe for the capture, determination, and drug resistance analysis of Gram-positive bacteria.

A multifunctional surface-enhanced Raman scattering (SERS) platform integrating sensitive detection and drug resistance analysis was developed for Gram-positive bacteria. The substrate was based on self-assembled Ti3C2Tx@Au NPs films and capture molecule phytic acid (IP6) to achieve specific capture of Gram-positive bacteria and different bacteria were analyzed by fingerprint signal. It had advantages of good stability and homogeneity (RSD = 8.88%). The detection limit (LOD) was 102 CFU/mL for Staphylococcus aureus and 103 CFU/mL for MRSA, respectively. A sandwich structure was formed on the capture substrate by signal labels prepared by antibiotics (penicillin G and vancomycin) and non-interference SERS probe molecules (4-mercaptobenzonitrile (2223 cm-1) and 2-amino-4-cyanopyridine (2240 cm-1)) to improve sensitivity. The LOD of Au NPs@4-MBN@PG to S. aureus and Au NPs@AMCP@Van to MRSA and S. aureus were all improved to 10 CFU/mL, with a wide dynamic linear range from 108 to 10 CFU/mL (R2 ≥ 0.992). The SERS platform can analyze the drug resistance of drug-resistant bacteria. Au NPs@4-MBN@PG was added to the substrate and captured MRSA to compare the SERS spectra of 4-MBN. The intensity inhomogeneity of 4-MBN at the same concentrations of MRSA and the nonlinearity at the different concentrations of MRSA revealed that MRSA was resistant to PG. Finally, the SERS platform achieved the determination of MRSA in blood. Therefore, this SERS platform has great significance for the determination and analysis of Gram-positive bacteria.